1. FIELD OF THE INVENTION
This invention relates to a stable liquid cleaning and bleaching composition comprising a surface active agent having a high biodegradability and an alkali metal hypochlorite.
2. DESCRIPTION OF THE PRIOR ART
Aqueous solutions of sodium hypochlorite are widely used for purposes of bleaching, disinfection, deodorization and the like. When such a solution is used especially for bleaching, in combination with a surface active agent, the bleaching effect is further enhanced by the permeating action and cleaning action owing to the presence of the surface active agent. This method is employed in the textile fiber industry. Likewise sodium hypochlorite-type bleaching agents are used simultaneously with washing detergents for general home laundry use. It would therefore be convenient if a surface active agent could be added to an aqueous solution of sodium hypochlorite in advance.
An aqueous solution of sodium hypochlorite, however, is a solution of a strong alkaline oxidizing agent and at the same time, it is an aqueous solution of an inorganic salt. For these reasons, decomposition of the surface active agent takes place (which results in further decomposition of the sodium hypochlorite), or the surface active agent is salted out, thereby inhibiting dissolution thereof in a large amount. These and other related problems are not yet solved in a completely satisfactory manner.
Various studies have been conducted to develop a surface active agent which can be added to aqueous sodium hypochlorite solutions to form a stable composition. The following are typical of such prior art attempts.
As the surface active agent for this purpose, Japanese Patent Publication No. 6268-63 discloses alkyldiphenylether sulfonate having the following formula (A) ##STR2##
Japanese Patent Publication No. 2103-68 discloses alkylphenylether sulfates having the following formula (B) ##STR3##
Japanese Patent Publication No. 24786-68 discloses sodium alkanesulfonates having the following formula (C) ##STR4##
Since waste waters from domestic cleaning generally find their way into streams and rivers, it is desirable that surface active agents have a high biodegradability. On the other hand, domestic cleaning water is usually city water or well water containing calcium ions (Ca.sup.++) and magnesium ions (Mg.sup.++). If a surface active agent has a poor hard water resistance, it is converted into metal salts of these metals, thereby lowering drastically its properties as a surface active agent.
In light of these factors, the above-mentioned agent (A) essentially has poor detergency and poor foaming properties. Although the agent (B) has good resistance against hard water, it contains, as the alkylphenyl moiety in the principal commercially available materials, octylphenyl, nonylphenyl or dodecylphenyl groups and as a consequence, it has poor biodegradability. Finally, the agent (C) has poor resistance against hard water and, in order to blend it stably at a low temperature, it must substantially be used conjointly with a solubilizing agent.